1. Field of the Invention
The present invention relates to a vehicle seat, and more particularly to an automobile seat having an improved mounting structure for securing a movable arm member of a reclining mechanism to a back frame constituting a seat back. The present invention is advantageous in that it is safer as compared to conventional vehicle seats since bolts for fixing the movable arm member do not project beyond the outer surface of the back frame and also in that it can eliminate the possibility of damaging the outer peripheral surface of the back frame when the movable arm member is fixed to the back frame.
2. Description of the Prior Art
In conventional vehicle seats in which there is mounted a reclining mechanism between a seat cushion and a seat back so as to be able to incline the seat back, and the back frame of the seat back has a pan-type structure formed of synthetic resin or steel plate, as shown in FIG. 1(A), the back frame (1) includes a rear surface (2) which is generally rectangular. On the periphery of the rear surface (2) there are provided upper, lower, right and left walls (4a), (4b), (4c) and (4d) and also at the convenient positions of the rear surface (2) there are arranged reinforcing ribs (5a), (5b) which extend longitudinally and transversely, respectively.
Also, with the end portions (6a) of the reclining mechanisms (6) being respectively fixed to a cushion frame, a pair of movable arm members each on a free hinge (not shown) are respectively abutted against the inner surfaces of the right and left walls (4c) and (4d) through grooves (7),(7) cut in the lower wall (4b) of the back frame (1) in a mutually opposing relation, and thereafter the movable arm members (6b) are respectively fastened to the right and left walls (4c), (4d) by means of bolts (9) and nuts (10) to provide an assembly.
However, when the movable arm members (6b) of the reclining mechanism (6) are assembled to the back frame (1) in the above described manner, as shown more clearly in FIG. 1(B), it is necessary to tighten the bolts (9) from the side of the outer surfaces of the right and left wall (4c) and (4d), which involves several disadvantages. For example, there is a possibility that the outer surface of the back frame (1) may be damaged by the tip end of a tool during the assembling operation. Also, the bolts may be dangerous to a seat occupant because the head portions of the bolts (9) project beyond the outer surfaces of the right and left walls (4c) and (4d). Moreover, the bolts used must be surface-treated with some high quality processes, such as a chrome plating so that the aesthetic appearance of the seat will not be impaired. Such processes however result in increased costs.